Bottlehead Forum

General Category => General Discussion => Topic started by: robertod on February 17, 2023, 06:05:30 AM

Title: follow the noise.
Post by: robertod on February 17, 2023, 06:05:30 AM
I have monoblocks, when i turn on my system, there is a crackle noise coming out of the left speaker. I upgraded some caps and resistors about 8 months ago and everything worked no crackle).
I removed the monoblock from system and check solder.  I noticed one connection was loose on a resistor. I re soldered the resistor, turned on system noise gone, so I thought.
Next day turned on system a slight crackle noise out of speaker again. (sounds Muffled).  I checked all solder joints they looked good. (re soldered a few that looked suspicious) crackle noise still there.
Today I moved monoblocks, Left one to the right and right to the left.  The noise followed the monoblock.

What else should I check for?  Thanks for your help and recommendations.
Title: Re: follow the noise.
Post by: Paul Birkeland on February 17, 2023, 06:13:25 AM
Swap the tubes.  Also keep in mind that any solder joint in the amp could cause a noise like this, not necessarily what is associated with the recent mods.
Title: Re: follow the noise.
Post by: robertod on February 17, 2023, 06:21:15 AM
Thanks for the reply.  I will swap tubes once system cools down.
Title: Re: follow the noise.
Post by: robertod on February 17, 2023, 07:22:28 AM
I could only swap tubes from one mono block to the other.  There was no crackle noise out of right or left speakers.  I'm wondering if the tubes were not seated correctly.
 
The 2A3's are 2 years old.
The 5y3's are 2+ years old.
The 6sn7's are 2+ years old.
Title: Re: follow the noise.
Post by: Paul Birkeland on February 18, 2023, 09:08:54 AM
It could just be a little pin oxidation.
Title: Re: follow the noise.
Post by: robertod on February 19, 2023, 05:30:17 AM
PB, thanks for your replay. Time to clean pins.  The tubes should be good for awhile or should I consider replacing the rectifier tube.
Last night all good no crackle and music sounds good.
Thanks again.
Title: Re: follow the noise.
Post by: robertod on February 25, 2023, 05:24:32 AM
Could a tube or tubes cause the crackle noise?
Title: Re: follow the noise.
Post by: Paul Birkeland on February 25, 2023, 07:31:05 AM
If the crackling noise is related to a specific tube, then the noise will follow that tube if you swap it to the other channel.
Title: Re: follow the noise.
Post by: robertod on February 25, 2023, 11:39:38 AM
okay thanks, I will do that this evening.
Title: Re: follow the noise.
Post by: robertod on February 25, 2023, 12:37:27 PM
moved the tubes to the right monoblock and noise followed.
Title: Re: follow the noise.
Post by: Paul Birkeland on February 26, 2023, 06:05:15 AM
If you move them one at a time, you may be able determine which one is crackling.
Title: Re: follow the noise.
Post by: robertod on February 27, 2023, 04:22:52 AM
I moved one and no noise.  It is the 5y3(rectifier).  I'm glad it was just the one tube.